Analog-to-digital converters (ADCs) convert time-discrete analog input values to a digital form. A type of ADC, the Σ-Δ modulator, digitizes the analog input values, and then analogizes the digital output signal by means of a digital-to-analog converter (DAC), generally feeding the analog value back to at least a subsequent analog input value. Σ-Δ modulators may be operated at a high frequency, making them usable in many communications applications. Accordingly, a distribution of the quantization noise, which results from quantization errors, can be achieved by means of a larger spectral range. The quantization noise can then be better eliminated from the digital output signal with the aid of suitable filters, for example.
One form of noise shaping, in the case of Σ-Δ modulators, includes shaping the quantization noise by feeding back a digital output signal (in analog form) to an earlier stage of the modulator, when the modulator is designed with multiple stages. In some examples, however, the use of multiple stages and/or a network of switched capacitors can result in a level of power consumption that is undesirable.